Nearly 17.4 million Americans are covered by HSA-eligible insurance plans, an increase of nearly 12 percent since 2013, according to a new census from AHIP.

Most enrollment gains in the HSA/HDHP space in 2014 were in the large group market. The share of HSA/HDHP lives enrolled in large group plans jumped from 59 percent in January 2012 to 68 percent in January 2013, to 74 percent in January 2014.

The census also reported:

Nationally, the average monthly premium was $371 for single coverage and $835 for families.

About half (52 percent) of all HSA/HDHP enrollees in the individual market (including dependents covered under family plans) were age 40 or over; 48 percent were under age 40.

The gender distribution of people covered by an HSA/HDHP as of January 2014 was evenly split — 50 percent male and 50 percent female.

AHIP has tracked the number of people covered by HSA/HDHPs since 2004 when Congress first authorized the model. Total enrollment in HSA plans has grown, on average, 15 percent annually since 2011.

“HSA plans are increasingly becoming an important and valuable coverage option for consumers and employers,” AHIP President and CEO Karen Ignagni said. “HSA plans provide important tools to support consumers and families in their health care decisions and to help them save for future medical expenses."